Note: Descriptions are shown in the official language in which they were submitted.
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Rubber mixtures containin~ PolvsulPhide pol~ether silanes
The present invention relates to novel rubber mixtures cont~ining polysulphide
polyether silanes and to the use of these rubber mixtures for the preparation of5 rubber vulc~ni~ates. The rubber mixtures according to the invention are suitable
for the production of mouldings, in particular for the production of tyres having a
low rolling resistance associated with a good wet skid resistance, a high abrasion
resistance as well as a high dynamic and thermal loading capacity.
10 A number of proposals have been formulated for solving the problem of producing
tyres having a decreased rolling resistance. In the German Offenlegungsschrift
documents 2 141 159, 2 141 160 and 2 255 577 and in US-PS 4,709,065, certain
organosilanes are described as reinforcing additives, in particular for rubber vul-
c~ni~tes containing silica. The use of such organosilanes for the production of
silica-filled tyre treads is also described in EP 447 066. Through the combination
of materials based on silica and of organosilanes, the rolling resistance of the tyres
has been successfully decreased without, as is otherwise usual, impairing the abra-
sion resistance and the wet skid resistance of the tyres. However, large quantities
of a costly silane raw material which is expensive to prepare are required for the
20 preparation of the above-mentioned classes of compounds.
DE-A 44 06 947 and DE-A 19 54 9027 describe oligomeric reinforcing additives
cont~ining sulphur and silicon which, with a lower content of costly silane raw
material, produce results equally as good as those for previously described com-
25 pounds having a higher silane content. A disadvantage, however, is that the solu-
bility of compounds above a certain molecular weight decreases owing to the highpolysulphide content and the addition of other non-polar solvents is necessary in
order to carry out the reaction. As a result of this at least part of the acquired ad-
vantages of the raw materials is lost owing to the greater expenditure on proces-
30 sing in the preparation.
It has now been found that certain polysulphide polyether silanes, despite the farhigher molecular weight, can be prepared in the same solvent as the low-molecular
silanes. Furthermore the polysulphide polyether silanes according to the invention,
35 despite their far lower Si content, when used as reinforcing additives in silica-
filled rubber vulcanisates are equally as effective as the low-molecular silanes and
possess additional advantages owing to improved vulcanisation kinetics in the
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preparation of vulcanisates as well as advantages in the
dynamic hysteresis of the vulcanisates.
The present invention therefore provides rubber
mixtures containing at least one rubber, a filler, optionally
additional rubber auxiliaries and at least one polysulphide
polyether silane corresponding to the formula
RlR R3Si-X -(-Sx-polyether-)m-(-Sx-X -SiR R R )n (I),
wherein
Rl, R and R3 are identical or different and denote
1 18 Y , Cl C18 alkoxy, C6-C12-phenyl or -phenoxy C -C
arylalkyl or alkylaryloxy, with the proviso that at least one
of the groups Rl to R3 is an alkoxy, phenoxy or alkylaryloxy
grOUp ~
xl and x2 are identical or different and represent
divalent, linear or branched or cyclic, optionally unsaturated
Cl-C12-alkyl groups,
polyether represents a bi-, tri- or tetrafunctional
polyethylene oxide polyether group, polypropylene oxide poly-
ether group, polybutylene oxide polyether group, or a
corresponding mixed polyether group having an average molecular
weight of from 300 to 5,000,
m represents an integer from 1 to 20,
n represents a number from 1 to 4, and
x denotes a number from 1 to 8,
the polysulphide polyether silane being used in
quantities of from 0.1 to 15 wt.~, based on the quantity of
the rubber used in each case. Optionally unsaturated alkyl
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is intended to include alkylene and alkyne.
The rubber mixtures according to the in~ention
contain preferably from 0.1 to 10 wt.% of polysulphide polyether
silane, particularly preferably 1 to 7.5 wt.%.
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The rubber mixtures according to the invention contain preferably those poly-
sulphide polyether silanes corresponding to the above formula, wherein Rl, R2 and
R3 independently of one another denote methyl, ethyl, propyl or phenyl, with theproviso that at least one of the groups Rl to R3 represents a methoxy, ethoxy,
S propoxy, butoxy or phenoxy group, and that Xl and x2 denote methylene,
propylene, butylene, pentylene or hexylene groups and that Y represents a poly-
ethylene oxide group, poly~ulopylene oxide group or a polyethylene oxide/poly-
propylene oxide mixed polyether group having molecular weights of between 300
and lS00, which has been obtained by addition of at least 6 moles ethylene oxide10 and/or propylene oxide to an aliphatic or aromatic diol or amine and wherein n
equals 1 and m denotes integers from 1 to 20.
Reinforcing additives corresponding to the formulae which follow below are
particularly preferred:
(R-0)3 Si-CH2CH2CH2--S--~~sx CH2CH2CH2- Si (OR)3 (1)
m
wherein R = CH3, C2H5, x = 1 to 8, p = S to 30, m = 1 to 20,
(R-0)3 Si -CH2CH2CH2 S--~O~SX--CH2CH2CH2- Si (OR)3 (2)
_ p
_ m
wherein R= CH3, C2H5, x = 1 to 8, p = S to 30, m = 1 to 20,
(R-0)3 Si -CH2CH2CH2 Sx~ \J~o~--~--Sx CH2CH2CH2- Si (OR)3 (3)
-- --a-- b --c
--m
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wherein R = CH3, C2H5, C3H7, x = 1 to 8, a= 3 to 20, b = 1 to 10, c = 3 to 20,
m = 1 to 20,
(R-0)3 Si -CH2CH2CH2--Sx~/ ~/\~'\0~/ ~\Sx--CH2CH2CH2- Si (OR)3
--m
(4)
wherein R= CH3, C2H5, C3H7, x = 1 to 8, a = 3 to 20, b = 2 to 20,
m= 1 to20,
(R-0)3 Si -CH2CH2CH2--Sx~/ ~/~/\o~ \sx--CH2CHZCH2- Si (OR)3
--m
(S)
wherein R= CH3, C2H5, C3H7, x = 1 to 8, a= 3 to 20, b = 2 to 20,
m = 1 to 20,
(R-0)3 Si -CH2CH2CH2--S~ ~ (6)
--3
wherein R= CH3, C2H5, C3H7, x = 1 to 8, a = 2 to 20,
(R-0)3 Si -CH2CH2CH2--Sx~/ ~\C411~ ~/--SX--CH2cH2cH2-si (OR)3
(7)
wherein R = CH3, C2H5, C3H7, x = 1 to 8, a = 3 to 20, b = 1 to 10,
m = 1 to 20.
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Particularly preferred polysulphide polyether silanes are those corresponding to the
following formula:
R1 \ R1
R2 /Si~CH--5~0/~m t ~3r R3
(8)
wherein Rl, R2, R3 denote methyl, phenyl, methoxy, ethoxy, propoxy, butoxy,
with the proviso that at least one of the groups is a methoxy, ethoxy, propoxy or
butoxy group. q, r = 1 to 3, x = 1 to 8, p = 6 to 30, m = 1 to 20.
The polysulphide polyether silanes according to the invention may be used eitherindividually or mixed with one another. In this connection either the individualcompounds having a defined molecular weight may be used or mixtures of oligo-
mers having a definite molecular weight distribution. For processing reasons, it is
easier to prepare a mixture of oligomers of the above-mentioned polysulphide
polyether silanes and to use them in this form. If the reinforcing additives are used
in the form of a mixture of oligomers, the latter has an average molecular weight
of about 800 to 10,000 as determined by gel permeation chromatography.
The novel polysulphide polyether silanes according to the invention may be
prepared in various ways:-
A) By the reaction of silanes cont~ining mercapto groups and dimercaptans
and/or polymercaptans with sulphur dichloride or sulphur dichloride, with
elimin~tion of HCl. The reaction may be carried out in a known per se
manner at temperatures of from -30~C to +80~C, optionally in the presence
of solvents, such as alcohols or aromatic hydrocarbons:
RlR2R3Si-X-SH+ HS-polyether-SH + SxCl2 ~
RIR2R3Si-Xx+2-(-polyether-Sx 2)m-X-SiRlR2R3 + HCl
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For details regarding carrying out the reaction, reference may be made to
Houben-Weyl, Methoden der organischen Chemie, Volume 9, pages 88 ff.,
(1955) and Volume E 11 (1985), Thieme Verlag, Stuttgart.
5 B) The polysulphide polyether silanes according to the invention may be
prepared particularly advantageously by reacting haloalkyl silyl ethers and
polyhalides with metal polysulphides in the presence of alcoholic solvents
at temperatures of from approximately -20~C to +90~C:
RIR2R3Si-X-Hal + Hal-polyether-Hal + MeSx ~
RIR2R3Si-X,~-(-polyether-Sx)m-X-SiRlR2R3 + MeHal
The metal polysulphides used are preferably those wherein Me represents lithium,sodium or potassium and x denotes a number from 2 to 8. The alcoholic solvents
used are preferably methanol, ethanol, propanol, butanol, amyl alcohol, hexyl alco-
hol, octanol, ethylene glycol and propylene glycol, butanediol and/or hexanediol as
well as isomers thereof.
The polysulphide polyether silanes according to the invention may be added either
in pure form to the rubber mixtures, or may be added thereto mounted on an inertorganic or inorganic support. Suitable support materials are in particular silicas,
naturally occurring or synthetic silicates, aluminium oxide and carbon blacks.
Suitable fillers include both the fillers which are active for the rubber vulcanisates
according to the invention and inactive fillers such as, for example:-
- Highly disperse silicas, prepared, for example, by precipitation from
solutions of silicates or by flame hydrolysis of silicon halides having
specific surfaces of 5 to 1000 m2/g, preferably 20 to 400 m2/g (BET
surface area) and having primary particle sizes of 100 to 400 nm. The
silicas may optionally also be present as mixed oxides with other metal
oxides, such as the oxides of Al, Mg, Ca, Ba, Zn, Zr and Ti.
- Synthetic silicates, such as aluminium silicates or alkaline-earth metal sili-
cates, such as magnesium silicate or calcium silicate, having BET surface
areas of 20 to 400 m2/g and primary particle diameters of 10 to 400 nm
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- Naturally-occurring silicates, such as kaolin and other naturally-occurring
silicas
- Glass fibres and glass fibre products (mats, strands) or glass microbeads.
- Aluminium hydroxide or magnesium hydroxide
- Carbon blacks. The carbon blacks to be used here are produced by the lampblack process, furnace process or gas black process and have BET
surface areas of 20 to 200 m2/g, for example, SAF, ISAF, HAF, FEF, or
GPF carbon blacks.
Highly-disperse silicas having BET surface areas of 20 to 400 m2/g are preferably
used.
The above-mentioned fillers are used in quantities of from 0 to 150 wt.%,
preferably 10 to 100 wt.%, based on the quantity of the rubber used in each case.
The above-mentioned fillers may be used on their own or mixed with one another.
20 In one particular embodiment, the rubber mixtures contain as fillers a mixture of
light-coloured fillers, such as highly-disperse silicas, and carbon blacks, the mixing
ratio of light-coloured fillers to carbon blacks being 0.05 to 20, preferably 0.1 to
10. The polysulphide polyether silanes (I) may be used on their own as cross-
linking agents. Other cross-linking agents which may be used for the rubber
25 mixtures according to the invention are, for example, sulphur and peroxides, to
which may also be added the known vulcanisation accelerators, such as mercapto-
benzothiazoles, mercaptosulphenamides, thiurams and thiocarbonates. Both the
vulcanisation accelerators and the cross-linking agents may be used individually or
mixed with one another. Sulphur is particularly preferred as a cross-linking agent.
30 The cross-linking agents and the vulcanisation accelerators are each used in
quantities of from 0.1 to 10 wt.%, preferably 0.1 to 5 wt.%, based on the rubberused in each case.
Other rubber auxiliaries may, of course, also be added to the rubber mixtures
35 according to the invention; examples of these additives are antioxidants, heat
stabilisers, light stabilisers, antiozonants, processing agents, plasticisers, tackifiers,
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blowing agents, dyes, pigments, waxes, extenders, organic acids, reaction retarders,
metal oxides, such as zinc oxide and magnesium oxide, as well as activators suchas triethanolamine, polyethylene glycol and hexanetriol, which are familiar to the
rubber technologist.
The above-mentioned rubber auxiliaries are added in conventional quantities (0.1to 50 wt.%, based on the rubber used in each case). The most favourable quantityof auxiliary substance used can easily be determined by prelimin~ry tests and
depends, incidentally, on the respective purpose of the rubber vulcanisates.
Besides natural rubber, synthetic rubbers are also suitable for the preparation of
rubber mixtures according to the invention. Preferred synthetic rubbers are
described, for example, in: W. Hofmann, Kautschl-kte~lnologie, Gentner Verlag,
Stuttgart, 1980. They include polybutadiene, butadiene-acrylic acid-CI 4-alkyl ester
copolymers, polychloroprene, polyisoprene, styrene-butadiene copolymers having
styrene contents of 1 to 60 wt.%, preferably 20 to 50 wt.%, isobutylene-isoprenecopolymers, butadiene-acrylonitrile copolymers having acrylonitrile contents of 5
to 60 wt.%, preferably 10 to S0 wt.%, partly hydrogenated or completely
hydrogenated butadiene-acrylonitrile copolymers and ethylene-propylene-diene
copolymers. The rubbers may, of course, also be used mixed with one another.
Rubbers which are of interest for the production of automobile tyres are in
particular anionically polymerised solution styrene-butadiene copolymers having a
glass temperature of above -50~C, which optionally may be modified with silyl
ethers or other functional groups, polybutadiene rubbers having a high 1,4-cis
content (> 90%), which are prepared using catalysts based on Ni, Co, Ti or Nd,
polybutadiene rubbers having a vinyl content of 0 to 75% and mixtures thereof
(see, for example, EP-A 447 066).
The rubber mixtures are prepared in the conventional manner, in known mixing
units, such as rolls, closed mixers and mixer-extruders, at composition tempera-tures of 100~C to 200~C and at shear rates of 1 to 1000 s~l.
The addition of the reinforcing additives according to the invention and the
addition of the fillers is carried out preferably during the first part of the mixing
process at composition temperatures of 100~C to 200~C and at the given shear
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g
rates. The additions may however also take place later at lower temperatures of
40~C to 100~C, for example, together with sulphur and vulcanisation accelerators.
The rubber mixtures according to the invention may be vulcanised in the conven-
5 tional manner (see, for example, G. Alliger, I.J. Sjothun, Vulc~ni7.~tion of Elasto-
mers, Reinhold Publishing Corporation, New York, 1964). The vulcanisation is
carried out at temperatures of from about 100~C to 200~C, preferably at 130~C to180~C, optionally at pressures of 10 to 200 bar.
10 The rubber vulc.~ni.c~tes according to the invention are particularly suitable for the
production of moulded articles, for example, for the manufacture of cable sheaths,
tubing, drive belts, conveyor belts, rollers, shoe soles, sealing rings and damping
elements, but preferably for the production of tyres.
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Examples
Example 1
5 Cl-terminated bifunctional polvethvlene oxide Polvether havin~ a molecular
wei~ht of aPprox. 400
238 g thionyl chloride was added over a period of two hours at a temperature of
50~C to 60~C to 400 g of a polyethylene glycol having an average molecular
weight of 400 and 0.5 g pyridine. The mixture was then heated by passing
nitrogen through it for 18 hours at 65~C to 70~C and degassed for a further 3
hours in a vacuum (20 mbar) at 70~C. 418 g of a colourless oil having a viscosity
of 40 mPa.s was obtained.
15 Elemental analysis:
C H Cl
calculated: 47.2 % 7.9 % 17.4 %
found: 47.2 % 7.8 % 15.5 %
Examnle 2
Cl-tern~in~ted bifunctional Polvethvlene oxide Polvether havin~ a molecular
wei~ht of aPprox. 600
The procedure was as described in Example 1, with 600 g of a polyethylene oxide
polyether having an average molecular weight of 600 being reacted with 238 g
thionyl chloride in the presence of 0.5 g pyridine. 624 g of a brown oil having a
viscosity of 90 mPa sec was obtained.
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Example 3
Cl-terminated bifunctional polyethvlene oxide polyether havin~ a molecular
wei~ht of approx. 900
The procedure was as described in Example 1, with 450 g of a polyethylene oxide
polyether having an average molecular weight of 900 being reacted with 119 g
thionyl chloride in the presence of O.S g pyridine. 454 g of an almost colourless
oil was obtained, which crystallised after a few days at room temperature. fp 35~C
10 to 40~C.
Elemental analysis:
C H Cl
calculated: 51.1 % 8.5 % 70 %
found: 51.3 % 8.5 % 7.4 %
Example 4
Cl-terminated bifunctional polyethylene oxide Polvether havin~ a molecular
wei~ht of approx. 1550
The procedure was as described in Example 1, with 750 g of a polyethylene oxide
polyether having an average molecular weight of 1500 being reacted with 119 g
thionyl chloride in the presence of 0.5 g pyridine. 755 g of an almost colourless
oil was obtained, which crystallised on being cooled to room temperature.
Elemental analysis:
C H Cl
calculated: 52.8 % 8.6 % 4.5 %
found: 52.8 % 8.6 % 4.4 %
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Example 5
(C2HsO)3Si- C3H6 - S4 - polyether- S4 - C3H6 - Si(OC2Hs)3
containing a polyethylene oxide polyether having an average molecular weight of
S approx. 600
78 g (1 mol) anhydrous sodium sulphide and 96 g (3 mol) sulphur were heated in
500 ml dry ethanol at 70~C for 30 minlltes. 240.8 g (1 mol) 3-chloropropyltrieth-
oxysilane was then added dropwise thereto, followed by 318.5 g (0.5 mol) of a Cl-
10 termin~ted polyethylene oxide polyether obtained as in Example 2 and the mixturewas stirred for 5 hours at 70~C. The mixture was cooled and then filtered and the
precipitated NaCI was filtered off. After evaporation, 604 g of a brown oil having
a viscosity of 230 mPa sec was obtained.
15 Elemental analysis:
C H S Si
calculated: 42.6 % 7.6 % 20.2 % 4.4 %
found: 42.7 % 7.4 % 20.3 % 4.8 %
Example 6
(C2HsO)3Si- C3H6 - S4 - polyether - S4 - C3H6 - Si(OC2Hs)3
cont~inin~ a polyethylene oxide polyether having an average molecular weight of
approx. 400
The procedure was as described in Example 5, with 78 g (1 mol) anhydrous
sodium sulphide and 96 g (3 mol) sulphur being heated in 500 ml dry ethanol at
70~C for 30 minutes. 240.8 g (1 mol) 3-chloropropyltriethoxysilane was then
added dropwise thereto, followed by 203.5 g (0.5 mol) of a Cl-terminated
polyethylene oxide polyether obtained as in Example 1 and the mixture was stirred
for S hours at 70~C. The mixture was cooled and then filtered and the precipitated
NaCI was filtered off. After evaporation, 506 g of a brown oil having a viscosity
of 120 mPa sec was obtained.
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Elemental analysis:
C H S Si
calculated: 40.7 % 7.4 % 25.6 % 5.6 %
found: 42.0 % 7.4 % 24.0 % 5.2 %
Example 7
(C2H5O)3si- C3H6- S4- polyether - S4- C3H6 - Si(O C2Hs)3
10 containing a polyethylene oxide polyether having an average molecular weight of
approx. 900
The procedure was as described in Example 5, with 62.4 g (0.8 mol) anhydrous
sodium sulphide and 76.8 g (2.4 mol) sulphur being heated in 500 ml dry ethanol
at 70~C for 30 minutes. 192.4 g (0.8 mol) 3-chlolopr~yltriethoxysilane was then
added dropwise thereto, followed by 381.2 g (0.4 mol) of a Cl-termin~ted
polyethylene oxide polyether obtained as in Example 3 and the mixture was stirred
for 5 hours at 70~C. The mixture was cooled and then filtered and the precipitated
NaCl was filtered off. After evaporation, 644 g of a brown oil having a viscosity
20 of 820 mPa sec was obtained, which crystallised after prolonged standing at room
temperature. fp 35~C.
Elemental analysis:
C H S Si
calculated: 44.9 % 7.9 % 16.2 % 3.6 %
found: 44.9 % 7.9 % 15.9 % 3.3 %
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Example 8
(C2HsO)3Si- C3H6 - S4 - polyether - S4 - C3H6 - Si(OC2Hs)3
cont~ining a polyethylene oxide polyether having an average molecular weight of
S approx. 1500
The procedure was as described in Example S, with 39 g (O.S mol) anhydrous
sodium sulphide and 48 g (l.S mol) sulphur being heated in S00 ml dry ethanol at70~C for 30 minutes. 120.4 g (O.S mol) 3-chloropropyltriethoxysilane was then
added dropwise thereto, followed by 375 g (0.25 mol) of a Cl-terminated
polyethylene oxide polyether obtained as in Example 4 and the mixture was stirred
for 5 hours at 70~C. The mixture was cooled and then filtered and the precipitated
NaCI was filtered off. After evaporation, 535 g of a brown oil was obtained,
which crystallised rapidly at room temperature. fp 50~C to 55~C.
Elemental analysis:
C H S Si
calculated: 47.7 % 8.2 % 11.8 % 2.6 %
found: 47.6 % 8.2 % 11.8 % 2.6 %
Example 9
(C2Hso)3si- C3H6 ~ (S4 - polyether)3 - S4- C3H6 - Si(O C2HS)3
containing a polyethylene oxide polyether having an average molecular weight of
approx. 400
The procedure was as described in Example 5, with 78 g (1 mol) anhydrous
sodium sulphide and 96 g (3 mol) sulphur being heated in 500 ml dry ethanol at
70~C for 30 minutes. 120.4 g (O.S mol) 3-chloropropyltriethoxysilane was then
added dropwise thereto, followed by 305.3 g (0.75 mol) of a Cl-terminated
polyethylene oxide polyether obtained as in Example 1 and the mixture was stirred
for S hours at 70~C. The mixture was cooled and then filtered and the precipitated
NaCl was filtered off. After evaporation, 496 g of a brown oil having a viscosity
of 720 mPa sec was obtained.
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Example 10: Solubility behaviour in ethanol
in each case 30 parts by weight of a polysulphide silyl compound were heated in
70 parts by weight of ethanol for 5 minlltes at 70~C, during which the solubility in
5 the heated solvent was assessed:
Silyl compound Complete solubility Si content
Examples according
to the invention:
Compound from Example 5 yes 4.7 %
Compound from Example 6 yes 5.6 %
Compound from Example 7 yes 3.7 %
Compound from Example 8 yes 2.7 %
Compound from Example 9 yes 2.9 %
Comparison Examples:
Ex. 2 of DE-OS 2,141,160 yes 10.4 %
Ex. 1 of DE-A 195 49 027 no 5.8 %
Ex. 2 of DE-A 195 49 027 no 4.6 %
Ex. 3 of DE-A 195 49 027 no 3.8 %
Ex. 5 of DE-A 195 49 027 no 4.8 %
25 The results of the tests show that the polysulphide polyether silanes according to
the invention, despite a lower content of costly silane raw material, exhibit a better
solubility in the reaction medium (ethanol), so that it is possible to avoid the use
of an expensive solvent mixture in the plepa~alion process.
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Example 11: Comparison of vulcanisation kinetics
The rubber mixtures below were prepared within 5 minutes at 140~C in a 1.5 1
kneader. Finally, sulphur and accelerator were added thereto on a roll at approx.
5 50~C. The vulcanisation kinetics were investigated at 160~C in the final mixtures
by means of a Monsanto rheometer MDR 2000.
C 1, _ Examples Examples accordmg
to the invention
A B C D E F G
Solution SBR Buna VSL 4020-0 (Bayer) 75 75 75 75 75 75 75
BR Buna CB 11 (Bayer) 25 25 25 25 25 25 25
Silica Vulkasil S (Bayer) 80 80 80 80 80 i0 80
Carbon black Corax N 339 (Degussa) 6.5 6.5 6.5 6.5 6.5 6.5 6.5
Arom. oil Renopal 450 (Fuchs) 32.5 32.5 32.5 32.5 32.5 32.5 32.5
ZnO 2.5 2.5 2.5 2.5 2.5 2.5 2.5
Stearic acid
~ ~ Vulkanox 4020 (Bayer) 1.5 1.5 1.5 1.5 1.5 1.5 1.5
Wax Antilux 654 (Rhein Chemie) 1.5 1.5 1.5 1.5 1.5 1.5 1.5
Polysulph. silane as in Ex. I of DE 19 549 027 6.5 0 0 0 0 0 o
Polysulph. silane as in Ex. 2 of DE 19 549 027 0 6.5 0 0 0 0 0
Polysulph. silane as m Ex. 3 of DE 19 549 027 0 0 6.5 0 0 0 0
Compound according to the invention Ex. 6 0 0 0 6.5 0 0 0
Compound according to the invention Ex. 5 0 0 0 0 6.5 0 0
Compound according to the invention Ex. 7 0 0 0 0 0 6.5 0
Compound accordingto the invention Ex. 9 0 0 0 0 0 0 6.5
CBS Vulkacit CZ (Bayer) 1.5 1.5 1.5 1.5 1.5 1.5 1.5
DPG Vulkacit D (Bayer) 2 2 2 2 2 2 2
Sulphur 1.5 1.5 1.5 1.5 1.5 1.5 1.5
r.~. time at 160~C
(TS 06) in minutes 2.4 2.2 2.1 2.8 3 3 2.6
Vl ' - time at 160~C
(t 90) in minutes 14.2 13.5 13.4 13.5 12.4 11.5 12
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It is clear that the rubber mixtures cont~ining the compounds according to the
invention exhibit a more favourable vulcanisation behaviour, that is, a longer
period of workability and a shorter vulcanisation time.
5 Example 12
The rubber mixtures below were prepared within 5 minutes at 140~C in a 1.5 l
kneader. Finally, sulphur and accelerator were added thereto on a roll at approx.
50~C.
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Comparison Examples according
Example to the invention
A B C
Solution SBR Buna VSL 5025-1 (Bayer) 75 75 75
BR Buna CB 24 (Bayer) 25 25 25
Silica Vulkasil S (Bayer) 80 80 80
Carbon black Corax N339 (Degussa) 6.5 6.5 6.5
Aromatic oil Renopal 450 (Fuchs) 8 8 8
ZnO 2.5 2.5 2.5
Stearic acid
Antiozonant Vulkanox 4020 (Bayer) 1.5 1.5 1.5
Wax Antilux 654 (Rhein Chemie) 1.5 1.5 1.5
Bis(triethoxysilylpropyl) tetrasulphide
acc. to DE 2,255,577 6.5 0 0
Compound as in Example 6 0 6.5 0
Compound as in Example 7 0 0 6.5
CBS Vulkacit CZ (Bayer) 1.5 1.5 1.5
DPG Vulkacit D (Bayer) 2 2 2
Sulphur 1.5 1.5 1.5
The rubber mixtures were then vulcanised for 45 minutes at 160~C. The resulting
vulcanisation properties were as follows:
Tensile stress at 100% elongation (MPa) 3.4 3.4 3.6
Tensile stress at 300% elongation (MPa) 13.7 14.5 13.2
Tensile strength (MPa) 19 18.2 17.9
Tear resistance (MPa) 35.1 43.1 40.2
Hardness (Shore A) at 23~C 73 73 74
Rebound elasticity at 23~C (%) 25 25 23
Rebound elasticity at 70~C (%) 46 48 46
From the vulcanisation properties it may be seen that the polysulphide polyether
silanes according to the invention, despite a considerably decreased content of
costly silane raw material as compared with prior art, lead to equal mechanical
CA 02231302 1998-03-06
Le A 32 283-Forei~n Countries
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properties and moreover bring about advantages in the improved relationship of
wet skid resistance to rolling resistance (greater difference between the rebound
elasticities at 23~C and at 70~C).
CA 02231302 1998-03-06
